The use of operating systems customized for the purpose of electronic device calibration is known. During manufacture, special calibration firmware including a factory operating system (“OS”) is programmed or loaded onto a flash memory chip, which is then soldered onto a main circuit board incorporated into an electronic device. The factory OS is customized to facilitate calibration and customization of the device.
Once the calibration and customization of the electronic device is completed, the special calibration firmware is replaced with shipping firmware that includes a shipping OS. It can be desirable to disable or remove the customized special calibration firmware as it can include security holes that are undesirable in the shipping electronic device. The functionality of the shipping OS is generally free of such security holes and complies with standardized specifications that permit interoperability between different electronic devices. For electronic devices having cellular communication functionality, such as mobile phones and two-way wireless email devices, the shipping OS is often customized for a particular network carrier. Such customizations can include, but are not limited to, graphical user interface images, the default settings for certain functionality (e.g. whether a Bluetooth radio is on or off), languages, fonts and the configuration of certain radio features.
A flash utility executing on an external computing device is typically employed to overwrite the contents of the flash memory chip via a universal serial bus (“USB”) cable. This process of loading the shipping firmware onto the assembled electronic device is time-consuming, taking two to three minutes. As a result, this stage of production is costly, requiring many computers and operators to be dedicated to this task.
If the final version of the shipping firmware is completed before manufacturing begins, it can be advantageous to load the shipping firmware onto the flash memory chip in place of the factory OS prior to soldering onto the main circuit board. In this case, the shipping firmware generally must include calibration functionality in order to enable the calibration of the electronic device during manufacture. While the shipping firmware no longer needs to be placed into flash memory after assembly, the presence of such functionality in the shipping firmware can introduce security flaws in the electronic device. Further, the shipping firmware that includes the calibration functionality is less time-efficient than the special calibration firmware for calibration and customization of the electronic device.